Usually patients with serious oral diseases or in acute attack, or patients with serious mental diseases, serious systemic diseases that cannot tolerate surgery, and minors, are not allowed to have dental implants. 1, oral diseases more serious or in acute attack: osteomyelitis, acute periodontitis, acute pericoronitis, or malignant oral tumors, poor oral hygiene, periodontitis alveolar bone resorption is very serious, are not Dental implants are recommended. When the above problems can be improved, dental implants can be performed after the doctor’s evaluation; 2. Severe mental illness: Patients with uncontrolled mental illness cannot cooperate with dental implant operations and postoperative care, and dental implants are generally not recommended. If patients with mental illness are reasonably treated, stable and conscious, dental implantation can be considered; 3, serious systemic diseases: such as patients suffering from severe diabetes, hypertension, heart disease, the disease is not controlled, dental implantation operation is not recommended, such as diabetic patients due to abnormal bone metabolism, in most cases it is difficult to form osseointegration after implantation, which may lead to dental implant failure; 4, minors: jaw bone The dental implants may affect the growth and development and are not recommended for the operation.